patch 8.0.0552: toupper and tolower don't work properly for Turkish commit https://github.com/vim/vim/commit/3317d5ebbe8304da82b8088446060afcae0012af Author: Bram Moolenaar <Bram@vim.org> Date: Sat Apr 8 19:12:06 2017 +0200 patch 8.0.0552: toupper and tolower don't work properly for Turkish Problem: Toupper and tolower don't work properly for Turkish when 'casemap' is empty. (Bjorn Linse) Solution: Check the 'casemap' options when deciding how to upper/lower case.

is<F4>foo
{'silent': 0, 'noremap': 0, 'lhs': 'foo<C-V>', 'mode': ' ', 'nowait': 0, 'expr': 0, 'sid': 0, 'rhs': 'is<F4>foo', 'buffer': 0}
{'silent': 1, 'noremap': 1, 'lhs': 'bar', 'mode': 'v', 'nowait': 0, 'expr': 1, 'sid': 0, 'rhs': 'isbar', 'buffer': 1}
{'silent': 0, 'noremap': 0, 'lhs': 'foo', 'mode': ' ', 'nowait': 1, 'expr': 0, 'sid': 0, 'rhs': 'bar', 'buffer': 1}
xrx
yRy
abcd